Power station comprising a condenser installation for the condensation of water vapour

ABSTRACT

The invention relates to a power station comprising a condenser installation ( 2 ) for the condensation of water vapour, said condenser installation being mounted on a supporting structure ( 8 ) and comprising heat exchanger elements ( 5 ) past which cooling air flows from below. The condenser installation ( 2 ) is arranged in such a way that a longitudinal side thereof is directly adjacent to a building structure of the power station ( 1 ). A turbine house ( 3 ) comprises at least one wind passage ( 6 ) through which cooling air flows and/or is sucked beneath the heat exchanger elements ( 5 ).

The invention relates to a power station comprising a condenser installation according to the features set out in the characterising clause of patent claim 1.

Condenser installations are used for cooling turbine- or process waste steam and have been employed for many years on a very large scale in the field of power engineering. The efficiency of a power station depends to a considerable degree on the condensation performance of the condenser installation, the local climatic conditions and the wind velocities and wind directions related thereto affecting the condensation performance to a substantial degree. For this reason, current construction designs of condenser installations include wind protection walls, surrounding the heat exchanger elements in their entirety in order to prevent recirculation of the heated cooling air.

It is furthermore important that all ventilators of the condenser installation are impinged by the flow as uniformly as possible. Higher, naturally occurring wind velocities may result in a local pressure drop below the ventilators. The affected ventilators are unable to convey sufficient cooling air, causing the condensation performance to decrease and possibly necessitating a reduction of the output of a turbine connected to the steam circuit.

The other extreme condition is that the condenser installation may possibly be located on the lee side of building structures, in particular on the lee side of the boiler room and the turbine house of a power station. Normally, a condenser installation is erected as closely as possible to the turbine house, i.e. immediately adjoining the turbine house, to keep the conducting paths short and to condense the water vapour as rapidly as possible. In order to ensure nevertheless an optimal impingement by the flow, condenser installations are already erected at a relatively elevated position, so as to permit substantially unimpeded impingement by the flow from all sides, i.e. regardless of the direction of the wind. However, practice has shown that in condenser installations, the suction room of which is arranged below the ventilators on the lee side of building structures, hot air recirculation occurs, namely at a location where the inflowing air, due to the local cross-sectional constriction, flows through the remaining free space between the building structure and the elevated condenser installation in downward direction at relatively high velocity and below the heat exchanger elements. This may cause the undesirable effect that in spite of installed wind protection walls heated cooling air is entrained by the inflowing cooling air and is passed underneath the heat exchanger elements, i.e. hot air recirculation occurs. As a result of the increased temperature of the cooling air the condensation performance decreases, which, in turn, adversely affects the efficiency of the power station.

Proceeding on this basis, it is the object of the invention to provide a power station including a condenser installation for condensing water vapour according to the features set out in the characterising clause of patent claim 1, wherein the hot air recirculation is reduced.

The object is attained in a power station having the features according to patent claim 1. Advantageous further developments of the inventive concept form the subject of the subsidiary claims.

Extensive studies have shown that the addressed problem of hot air recirculation may be solved in a particularly cost-effective manner in that building structures, neighbouring the condenser installation, include tunnel-like wind passages, through which cooling air flows and/or is sucked under the heat exchanger elements. The wind passages are in particular provided in turbine houses and do not require any structures which would have to be erected separately. It is important that the free spaces, free of built structures, possibly existing in any case between boiler rooms, are opened towards the condenser installation so that incoming air may flow close to the ground through the space between the boiler rooms and into the wind passages of the turbine house, thus not having to follow the longer path, involving risks of recirculation, via the roofs of the boiler- and turbine rooms, but entering the suction room of the condenser installation directly from below. The configuration, i.e. in particular the dimensioning of the wind passages, is realised according to requirements and by taking into account the locally prevailing wind conditions, climatic conditions as well as further influencing parameters so that it may be ensured that the condenser installation operates without recirculation up to predetermined wind velocities, even if the condenser installation is located on the lee side of building structures of the power station. The solution according to the invention permits to comply better with warranty undertakings, e.g. if the power station operator is required to operate the condenser installation at wind velocities above 3 m/s without recirculation. Due to the complex flow conditions, the condenser installation cannot be designed by analytical methods, but only by numerical calculation methods. By means of CFD-processes (Computational Fluid Dynamics) it is possible to compare different configurations and layouts of the building structures and to analyse in this manner local flow phenomena, which can be measured only with difficulty or not at all. As a result of the multitude of parameters and the size of today's newly built power stations very complex calculation models come about, which alone often make it possible to localise the known problem of hot air recirculation in the first place.

It is, of course, always possible to erect very high wind protection walls on the periphery of the heat exchanger elements so that the heated cooling air will under no circumstances mix with the drawn-in cooling air. However, the investment costs for the erection of modern power stations are considerable so that one must look for cost-effective alternatives and supporting measures. By providing wind passages inside building structures, hitherto closed, there are provided not only new flow lines for feeding cooling air, but, in addition, effective possibilities present themselves for reducing the influence of the wind on the efficiency of the power station accompanied simultaneously by low investment costs.

It is considered to be advantageous for wind gates to be provided in order to vary the flow-through area of the wind passages. The width of the wind passages is often predetermined by structural necessities. Often these spacings will hardly allow any variation. However, wind gates can control in a relatively precise manner which amount of air is to be passed through the wind passages. The wind gates are normally fully opened in order to permit an unimpeded passage of the inflowing air. Vice versa, it is likewise possible to close the wind gates at least partially, if the wind velocity is too high or if the wind direction has changed. In particular, the wind gates may be coupled by means which permit to control the flow-through area as a function of the wind direction. It might, for example, be a drawback if the boiler and turbine rooms instead of the condenser installation were to be located on the lee side. In this case, it is more advantageous to keep the wind gates closed so that a certain dynamic pressure is formed underneath the heat exchanger elements, which may be increased by closing the wind gates. The decisive factor is ultimately that the condenser installation may “breathe”, i.e. that it receives cooling air, regardless of the wind direction, in a manner preventing hot air recirculation.

The invention is elucidated in more detail in what follows by way of a working example illustrated in the drawings. There is shown in:

FIGS. 1 and 2 two perspective illustrations of a power station model according to the state of the art;

FIGS. 3 and 4 two perspective illustrations of a power station model according to the solution proposed by the invention;

FIG. 5 a model showing the flow conditions in a power station according to the state of the art and

FIG. 6 a model showing the flow conditions in a power station according to the invention.

FIG. 1 shows a calculation model of a power station 1 including a condenser installation 2 for condensing water vapour which is fed to the condenser installation 2 from a turbine house 3. The turbine house 3 is positioned upstream of a boiler room 4. The turbine house 3 and the boiler room 4 are denoted overall as building structures of the power station. The wind direction W is symbolised by the illustrated arrow. The wind velocity is, for example 7m/s. By means of the varying shades of grey, the temperature pattern of the heated cooling air, emanating from the heat exchanger elements 5, can be detected, in which context, in particular, the circled section is of interest. There, it can be seen that evidently in the region of the longitudinal side of the condenser installation 2, adjoining the turbine house 3 and the boiler room 4, a portion of the heated cooling air enters into the heat exchanger elements 5 from below. This is noticeable from the illustrated temperature drop of the cooling air. In this case, hot air recirculation occurs despite existing wind protection walls.

It is apparent from FIG. 2, by way of the illustrated flow lines, that hot air recirculation does not only occur in the circled corner region of the illustrated condenser installation, but also in the region of the lee side behind the boiler and turbine houses 3, 4. The reason for this is apparent from FIG. 5. The illustrated arrows in FIG. 5 show the local wind direction. The length of the arrows indicates the local wind velocity. The power station 1 impinged by the flow from the right in the image plane includes a condenser installation 2, located on the lee side of the building structure of a power station, i.e. the boiler room 4 and, in particular, the turbine house 3. Although the condenser installation 2 is arranged in a highly elevated position, the spatial proximity to the turbine house 3 results in that the oncoming wind from the right in the image plane, must be drawn through a relatively narrow region under the heat exchanger elements 5 of the condenser installation 2. The large number and density of the individual arrows in this region shows that relatively high wind velocities prevail there. These high wind velocities, in turn, result in that on the edges of the condenser installation 2 as well, in the circled section, hot air emerging from the heat exchanger elements 5 is entrained and flows again under the condenser installation 2.

The concept of the invention now provides that the building structure bringing about the wind-sheltered region, i.e. in this case the turbine house 3, includes tunnel-like wind passages 6, through which cooling air flows and/or is sucked under the heat exchanger elements 5. FIG. 3 shows that the turbine house no longer presents a barrier to the cooling air flowing between the boiler houses 4, but rather defines a wind passage 6, which, by way of a wind gate 7, merely hinted at in the drawing, is flow-connected to the suction room below the condenser installation 2. The wind passage is guided through the turbine house 3 in tunnel fashion, as it were.

Theoretically it would be conceivable to subdivide the turbine house into individual sections, so that individual structures come about, situated side-by-side. However, the shared use of the infrastructure will then likewise be interrupted. In particular, with a view to using a travelling crane, tunnelling represents an economically sensible solution.

The illustration in FIG. 4 shows that the wind passages 6 enter below the heat exchanger elements 5 of the condenser installation 2, which heat exchanger elements are arranged on a supporting structure 8, so that the air emanating from the wind passages 6 need not be drawn in entirely via the roofs of the turbine houses 3 and boiler rooms 4, but may also be supplied directly to the condenser installation 2 via the wind passages 6.

By way of FIG. 6 it can be seen that in a sectional plane through the wind passage 6 a substantial portion of the drawn-in or inflowing cooling air of the condenser installation 2 is supplied by the wind passage 6. The portion is at least large enough to exclude any further occurrence of hot air recirculation in the region illustrated in FIG. 5 and, consequently, any impairment of the efficiency of the power station.

REFERENCE NUMERALS

-   -   1—Power station     -   2—Condenser installation     -   3—Turbine house     -   4—Boiler house     -   5—Heat exchanger element     -   6—Wind passage     -   7—Wind gate     -   8—Supporting structure     -   W—Wind direction 

1-4. (canceled)
 5. A power station with a condenser installation for condensing water vapor, comprising: a building structure with a tunnel-like wind passage, and a condenser installation comprising a supporting structure and heat exchanger elements arranged on the supporting structure and exposed to a cooling air flow, wherein a longitudinal side of the condenser installation is arranged in immediate proximity to the building structure, and wherein the cooling air flows or is suctioned through the tunnel-like wind passage and impinges on the heat exchanger elements from below.
 6. The power station according to claim 5, further comprising a turbine house, with the wind passage extending through the turbine house.
 7. The power station according to claim 5, further comprising wind gates for varying a flow-through area of the wind passages.
 8. The power station according to claim 7, further comprising control means coupled to the wind gates, said control means controlling a flow-through area as a function of wind direction. 